“The irony is that the Nazi holocaust has now become the main ideological weapon for launching wars of aggression,” Norman Finkelstein tells Yoav Shamir in “Defamation,” the Israeli filmmaker’s award-winning 2009 documentary on how perceptions of anti-Semitism affect Israeli and U.S. politics. “Every time you want to launch a war of aggression, drag in the Nazi holocaust.” If you’re looking for evidence in support of Finkelstein’s thesis today, you need look no further than the U.S. Holocaust Memorial Museum’s exhibit of images of emaciated and mutilated bodies from contemporary Syria.